Question

Amongst the following, the vector quantity is
(A). Pressure
(B). Gravitational potential
(C). Stress
(D).Impulse
(E). Distance

Answer 1

Hint – In this use the basics definitions of the vector and scalar quantity. Use them to check that amongst which of the following options the quantity involved has both direction as well as magnitude this can be termed as vector but however the ones with only magnitude and not direction is termed as scalar quantity.

Complete step-by-step solution -
As we know there are two types of quantity in a physical world:
$\left( 1 \right)$ Scalar quantity
$\left( 2 \right)$ Vector quantity.
Now scalar quantities are those which have only magnitude but not specific direction.
For example: Mass, energy, power, pressure, gravitational potential, stress, distance etc.
And vector quantities are those which have magnitude as well as specific direction.
For example: Force, acceleration, impulse etc.
Now as we all know inside a cylinder force per unit area is the same at every point which is called pressure therefore, pressure is a scalar quantity.
Now we all know that the unit of distance is either meter or centimeter so it has only magnitude that’s why it is a scalar quantity not a vector quantity.
Now as we all know that stress is the ratio of the pressure to the strain, as strain in change in length to the original length so strain is dimensionless so the unit of stress is depend upon the pressure as we see above that pressure is a scalar quantity so stress is also a scalar quantity.
Now as we all know that the gravitational potential has only magnitude it has no direction so it is also a scalar quantity.
Now impulse is a change in momentum so it has both magnitude as well as direction so it is a vector quantity.
So from among options only impulse is a vector quantity.
Hence option (D) is the correct answer.

Note – There is a very important consideration that we generally ignore while dealing with vectors, a vector is one which has both direction as well as magnitude but however it must obey all the laws of vector. For example current can be considered as a quantity that has both magnitude as well as direction but however it does not obey vector laws and thus it is scalar quantity only.